Articulating retrieval devices

ABSTRACT

The devices and methods described herein relate to improved structures for removing obstructions from body lumens. Such devices have applicability in through-out the body, including clearing of blockages within the vasculature, by addressing the frictional resistance on the obstruction prior to attempting to translate and/or mobilize the obstruction within the body lumen.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation of U.S. patent applicationSer. No. 11/852,975, filed on Sep. 10, 2007, which is acontinuation-in-part of U.S. patent application Ser. No. 11/736,537,filed Apr. 17, 2007, now U.S. Pat. No. 8,512,352, both of which areincorporated by reference herein in their entirety.

FIELD OF THE INVENTION

The devices described herein are constructed in wire form where thewires diverge from a main bundle to form a variety of shapes that form acomposite device. The benefit of such a diverging wire construction isthat the composite complex device can be of a “joint-less” construction.Such devices have applicability throughout the body, including clearingof blockages within body lumens, such as the vasculature, by providing acapturing portion that can envelop the obstruction to address thefrictional resistance between the obstruction and body lumen prior toattempting to translate and/or mobilize the obstruction within the bodylumen. In addition, the devices described below include features thatprevent unwanted and premature mobilization of the obstruction whenremoving the obstruction through tortuous anatomy.

BACKGROUND OF THE INVENTION

Many medical device applications require advancement of device in areduced profile to a remote site within the body, where on reaching atarget site the device assumes or is deployed into a relatively largerprofile. Applications in the cerebral vasculature are one such exampleof medical procedures where a catheter advances from a remote part ofthe body (typically a leg) through the vasculature and into the cerebralregion of the vasculature to deploy a device. Accordingly, the deployeddevices must be capable of achieving a larger profile while being ableto fit within a small catheter or microcatheter. In addition, the degreeto which a physician is limited in accessing remote regions of thecerebral vasculature is directly related to the limited ability of thedevice to constrain into a reduced profile for delivery.

Treatment of ischemic stroke is one such area where a need remains todeliver a device in a reduced profile and deploy the device toultimately remove a blockage in an artery leading to the brain. Leftuntreated, the blockage causes a lack of supply of oxygen and nutrientsto the brain tissue. The brain relies on its arteries to supplyoxygenated blood from the heart and lungs. The blood returning from thebrain carries carbon dioxide and cellular waste. Blockages thatinterfere with this supply eventually cause the brain tissue to stopfunctioning. If the disruption in supply occurs for a sufficient amountof time, the continued lack of nutrients and oxygen causes irreversiblecell death (infarction). Accordingly, immediate medical treatment of anischemic stroke is critical for the recovery of a patient.

Naturally, areas outside of ischemic stroke applications can alsobenefit from devices that can assume a profile for ultimate delivery toremote regions of the body.

Accordingly, a need remains for devices that can assume deployedconfigurations and are fabricated to eliminate or reduce the number ofjoints and/or connection points in the device. Elimination of the jointsalso allows the device to have a compact and smooth configuration makingit easier for delivery through a microcatheter, and leads to a saferdevice less prone to breaking or embolizing. Another need remains for adevice that can translate over and securely remove the obstruction fromtortuous anatomy.

SUMMARY OF THE INVENTION

The examples discussed herein show the inventive device in a form thatis suitable to retrieve obstructions or clots within the vasculature.The term obstructions may include blood clot, plaque, cholesterol,thrombus, naturally occurring foreign bodies (i.e., a part of the bodythat is lodged within the lumen), a non-naturally occurring foreign body(i.e., a portion of a medical device or other non-naturally occurringsubstance lodged within the lumen.) However, the devices are not limitedto such applications and can apply to any number of medical applicationswhere elimination or reduction of the number of connection points isdesired.

In one variation of the devices described herein, the device comprises amain bundle or group of wires that diverge to form a device havingvarious shapes but few or no connections points or joints (wherefabrication of such a construction is referred to as “jointless”).Clearly, the inventive devices described herein are not limited to sucha jointless construction. Additional variation includes one or moreleading wires that are attached to a capturing portion as describedbelow.

In one variation, the device includes a main bundle comprising one or agroup of wires. The device also includes a capturing portion formed bythe wires or wire of the main bundle. The capturing portion includes acavity or space that is able to surround the obstruction. Accordingly,the capturing portion includes an open proximal end, a permeable distalend, and a capturing surface extending therebetween. The permeabledistal end should be sufficiently permeable to allow blood to flow buthave sufficient surface area to prevent escape of the obstruction or toprevent particles such as pieces of clot or emboli that would otherwisecause a complication if such pieces migrate through the body. In somevariations of the device, the capturing portion is formed from the groupof wires such that the group of wires diverges from the second end ofthe main bundle to form the permeable distal end, the group of wiresextend back in a proximal direction to form the capturing surface andopen proximal end about the main bundle, such that articulation of thecapturing portion relative to the main bundle does not cause the openproximal end to reduce in size. Although some closing of the openproximal end can occur, it will not be sufficient to interfere with theobstruction as the capturing portion moves over the obstruction. In somevariations, the permeable end may be the distal end or be towards thedistal end (meaning anywhere past a proximal end). The terms distal andproximal are relative to the physician (e.g., the distal end is thefarthest end from the catheter/physician).

The devices of the present invention typically include a main bundlefrom which the wires extend. In most case, the main bundle extends for alength sufficient to withdraw the device from a body of a patient.Accordingly, in such cases, the main bundle shall extend through thelength of a catheter. In alternate constructions, the main bundle may beaffixed to a single wire or member. In such cases, a main bundle doesnot extend from the capturing portion to the exterior of the patient.Instead, a single wire extends to the operator interface of the devicewhere the wire is affixed to a main bundle.

Devices of the present invention can incorporate any number of wires ofdifferent characteristics including, but not limited to, materials,shapes, sizes and/or diameters. Clearly, the number of permutations ofdevice configurations is significant. Providing devices with such acomposite construction allows for the manipulation of the device'sproperties to suite the intended application.

In an additional variation, the surface of the capturing portion caninclude a wire frame structure, a mesh, a single wound wire, a film, amembrane, a polymer covering, and a plurality of crossing wires or aheterogeneous mixing of these. In additional variations, a section ofthe capturing portion can include wires, while another section of thecapturing portion can include a film. Clearly, any number ofpermutations is within the scope of this disclosure. In any case, thecapturing surface should prevent the obstruction from escaping as thedevice is removed from the body. Clearly, the capturing surface cancomprise any number of shapes or configurations.

As noted herein, the joint-less construction improves the flexibilityand strength of the device by eliminating joints, connection points, orother attachment points. In addition, the joint-less constructionimproves the ability of the device to be delivered through a smallmicrocatheter. As a result, the device and microcatheter are able toaccess remote regions of the vasculature.

The devices may be fabricated to be self-expanding upon deployment froma catheter. Alternatively, the devices can be constructed fromshape-memory alloys such that they automatically deploy upon reaching apre-determined transition temperature.

The devices of the present invention may also include features toprevent migration of the obstruction as the capturing portionencapsulates the obstruction. For example, a proximal foot (such asregion of increased surface area) can be located on or in the catheter.In another variation, an additional capture portion is located on thecatheter where the proximal end of this capture is a mesh, a singlewound wire, a film, a membrane, a polymer covering, or a plurality ofcrossing wires affixed to or in the catheter. Accordingly, the capturingportions both envelope or surround the obstruction as they are movedtogether. As noted below, additional variations may allow fortemporarily locking of the two capturing portions together for increaseeffectiveness in removing the obstruction from the body.

The operation of the devices and method described herein secure theobstruction, overcome the friction forces acting on the obstruction, andthen remove the obstruction from the anatomy without losing orfractionating the obstruction. In one variation of the invention, thisis accomplished by the obstruction removal device interacting with theobstruction in the following manner: (1) a catheter passes distal to theobstruction by passing either through the obstruction and/or between theobstruction and the vascular wall; (2) a first capturing portion isdeployed distally to the obstruction and the catheter is withdrawnproximal to the obstruction; (3) the capturing portion is thentranslated over the obstruction by withdrawing the main bundle. Sincethe main bundle is affixed to a distal end of the capturing portion,misalignment between the bundle and the capturing portion does not causedistortion of the open proximal end. Since the open proximal end remainsexpanded against the lumen wall, the capturing portion can then beadvanced over the obstruction.

The method and systems may also include the use of an additionalcapturing portion having an open distal end. This configuration allowsthe first capturing portion and second capturing portion to envelop orensnare the obstruction from both the proximal and distal sides.Additional variations even allow for temporarily locking the twocapturing portions together. Such a feature increases the ability toremove the obstruction from the body

It should be noted that reference to surrounding, capturing or securingthe obstruction includes partially and/or fully surrounding, engulfing,encapsulating, and/or securing the obstruction. In any case, a portionof the device engages the obstruction prior to translation of theobstruction within the lumen.

It should be noted that in some variations of the invention, all or someof the device can be designed to increase their ability to adhere to theobstruction. For example, the wires may be coupled to an energy source(e.g., RF, ultrasonic, or thermal energy) to “weld” to the obstruction.Application of energy to the device can allow the surrounding portion todeform into the obstruction and “embed” within the obstruction.Alternatively, the device can impart a positive charge to theobstruction to partially liquefy the obstruction sufficiently to allowfor easier removal. In another variation, a negative charge could beapplied to further build thrombus and nest the device for better pullingforce. The wires can be made stickier by use of a hydrophilicsubstance(s), or by chemicals that would generate a chemical bond to thesurface of the obstruction. Alternatively, the filaments may reduce thetemperature of the obstruction to congeal or adhere to the obstruction.

Additional devices and methods for treating ischemic stroke arediscussed in commonly assigned U.S. patent application Ser. No.11/671,450 filed Feb. 5, 2007; Ser. No. 11/684,521 filed Mar. 9, 2007;Ser. No. 11/684,535 filed Mar. 9, 2007; Ser. No. 11/684,541 filed Mar.9, 2007; Ser. No. 11/684,546 filed Mar. 9, 2007; Ser. No. 11/684,982filed Mar. 12, 2007, Ser. No. 11/736,526 filed Apr. 17, 2007 and Ser.No. 11/736,537 filed Apr. 17, 2007; the entirety of each of which isincorporated by reference. The principles of the invention as discussedherein may be applied to the above referenced cases to produce devicesuseful in treating ischemic stroke. In other words, the wire-shapedconstruction of devices according to present invention may assume theshapes disclosed in the above-referenced cases when such a combinationis not inconsistent with the features described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

Each of the following figures diagrammatically illustrates aspects ofthe invention. Variation of the invention from the aspects shown in thefigures is contemplated.

FIG. 1A illustrates an example of a device according to the presentinvention when used in a system for removing obstructions from bodylumens.

FIGS. 1B to 1D illustrates a first variation of the device having ajoint-less construction of a capturing portion that articulates about amain bundle of wires.

FIGS. 2A to 2L illustrate various constructions of capturing portionsfor use in the present invention.

FIG. 3A illustrates a main bundle having a curved or shaped portion.

FIGS. 3B to 3D illustrate wires of different constructions within a mainbundle.

FIG. 4A illustrates am example of a proximal foot located on a catheterof the present system.

FIG. 4B illustrates a distal and a proximal capturing portion located ona system under the present invention.

FIGS. 4C to 4E illustrate an overview of a variation of a deliverysystem employing a proximal and distal capturing portion.

FIG. 4F illustrates compression or collapsing of a proximal capturingportion about an obstruction prior to translation of the obstruction inthe vessel.

FIG. 5A illustrates closure of the proximal opening of a capturingportion without the benefit of articulation of the capturing portionabout a leading wire.

FIG. 5B illustrates, conceptually, one benefit of articulation of acapturing portion about a leading wire or main bundle of wires.

FIGS. 6A to 6E illustrate an example of the removal of an obstructionfrom a body lumen using one variation of a system under the presentinvention.

FIG. 6F illustrates a device after securing an obstruction betweenproximal and distal capturing sections.

FIGS. 7A to 7B illustrate coverings for use with capturing portions ofthe present invention.

FIGS. 8A to 8B illustrate an additional set of fibers within capturingportions, where the fibers improve retention of the clot within thedevice.

FIG. 9 illustrates a main bundle as including an increased surface areaor medial foot that is used to dislodge or loosen the obstruction from awall of the body passage.

DETAILED DESCRIPTION

It is understood that the examples below discuss uses in the cerebralvasculature (namely the arteries). However, unless specifically noted,variations of the device and method are not limited to use in thecerebral vasculature. Instead, the invention may have applicability invarious parts of the body. Moreover, the invention may be used invarious procedures where the benefits of the method and/or device aredesired.

FIG. 1A illustrates a system 10 for removing obstructions from bodylumens as described herein. In the illustrated example, this variationof the system 10 is suited for removal of an obstruction in the cerebralvasculature. Typically, the system 10 includes a catheter 12microcatheter, sheath, guide-catheter, or simple tube/sheathconfiguration for delivery of the obstruction removal device to thetarget anatomy. The catheter should be sufficient to deliver the deviceas discussed below. The catheter 12 may optionally include an inflatableballoon 18 for temporarily blocking blood flow or for expanding thevessel to release the obstruction.

It is noted that any number of catheters or microcatheters maybe used tolocate the catheter/microcatheter 12 carrying the obstruction removaldevice 200 at the desired target site. Such techniques are wellunderstood standard interventional catheterization techniques.Furthermore, the catheter 12 may be coupled to auxiliary or supportcomponents 14, 16 (e.g., energy controllers, power supplies, actuatorsfor movement of the device(s), vacuum sources, inflation sources,sources for therapeutic substances, pressure monitoring, flowmonitoring, various bio-chemical sensors, bio-chemical substance, etc.)Again, such components are within the scope of the system 10 describedherein.

In addition, devices of the present invention may be packaged in kitsincluding the components discussed above along with guiding catheters,various devices that assist in the stabilization or removal of theobstruction (e.g., proximal-assist devices that holds the proximal endof the obstruction in place preventing it from straying during removalor assisting in the removal of the obstruction), balloon-tipped guidecatheters, dilators, etc.

FIG. 1B illustrates a first example of a device according to thefeatures described herein. As shown, the device 200 generally includes amain bundle 202 comprising a group of individual wires 204. While theexample shows the group consisting of two individual wires 204, thebundle may have any number of wires. In various examples 2, 4, or 8wires were used to construct the device. In certain variations, thenumber of wires in the main bundle loop around from the capturingportion. For example, if 2 wires are used to construct the device, thenwhen constructing the main bundle 2 wires are set to extend distallytowards the capturing portion, where the 2 wires are then shaped to formthe capturing portion. Eventually, the wires then loop back to extendproximally away from the capturing portion. Therefore, the 2 wires aredoubled in the main bundle to create 4 separate wires in the mainbundle.

The individual wires 204 themselves may be comprised of a number ofdifferent “micro” filaments, wires, or a single type of wire. Variationsof the wires 204 are discussed in detail below; however, the wires 204can be strands, filaments, or any similar structure that is able to bejoined to form the device. The bundle 202 may be braided, wrapped,twisted, or joined in any manner such that they do not separate orbecome unbundled except where desired. For example, wires in any sectionof the device 200 can be bonded together (e.g., with epoxy, a polymericcoating, weld, solder, and/or adhesive, etc.) to prevent the wires fromseparating during deformation of the device as it deploys or removes theobstruction. In addition, the main bundle 202 can incorporate any numberof features to assist in orienting the device 200 within the bodypassage. For example, the main bundle 202 can include a pre-set bendthat would bias the capturing portion in a desired orientation upondeployment as discussed below (FIG. 2G).

The device 200 also includes a capturing portion 226. This capturingportion 226 may comprise such constructional designs as a basket, afilter, a bag, a coil, a helical wire structure, a mesh, a single woundwire, a film, a membrane, a polymer covering, or a plurality of crossingwires. In variations of the device, the capturing portion 226 issufficiently permeable to allow blood or other fluid flow therethrough.As noted above, capturing portion 226 may be any structure that covers,encapsulates, engulfs, and/or ensnares the obstruction either fully orpartially. Accordingly; although the capturing portion 226 isillustrated as a filter/bag, the wires may diverge to form a coil,helical shape, other mesh structure, or any other structure that definesa space that can be translated over the obstruction to ultimately removethe obstruction 2.

The capturing portion 226 includes an open proximal end 228, a permeabledistal end 230 and a capturing surface 232 located therebetween. Thesurface 232 of the capturing portion 226 defines a volume, cavity, orspace that is able to cover, encapsulate, envelop, engulf, ensnareand/or surround the obstruction. Generally, the term traversing wire orfilament refers to the section of wire 204 that forms the capturingsurface 232. Generally, the traversing wires form the capturing surface232 and then form the open proximal end 228. As discussed herein andillustrated below, the open proximal end 228 expands within the lumen,typically to the lumen walls, so that the obstruction enters the openproximal end 228 as the bundle 202 translates the device 200 proximally.In most devices, the open proximal end 228 is designed to provide a lowfriction surface so that it translates over the obstruction withoutmoving the obstruction significantly. The capturing surface 232 has anincreased frictional surface so that it can capture and ultimatelyremove the obstruction. The frictional surface can also be described asa coverage density. In essence, as the frictional surface/coveragedensity increases, there is more “device” surface area to interact withthe obstruction. In some variations the capturing surface has anincreasing frictional surface between the open proximal end and thepermeable distal end.

The permeable distal end 230 is typically sufficiently porous so thatfluid or blood may flow through. However, the end 230 is sufficientlyclosed (or has an increased surface area) so that the obstruction shouldnot escape through the distal end 230 of the device 200. The obstructionbecomes ensnared within the capturing portion 226 and is prevented frompassing through by the permeable distal end 230.

One important feature of the present devices is that the main bundle 202and capturing portion 226 can articulate relative to one another withoutinterfering with the size or profile of the open proximal end 228. Thisfeature is described more fully in FIGS. 5A to 5B below. As shown, themain bundle 202 extends through the open proximal end 228 and through atleast a portion of the capturing portion 226. In FIG. 1B, the mainbundle 202 and the group of wires 204 branch or diverge at the permeabledistal end 230 to form the capturing portion 226. In FIG. 1C, the mainbundle 202 branch or diverge within a mid-portion or at the capturingsurface 232 rather than at the permeable distal end 230. In such a case,the wires 204 form the capturing surface 232 first and ultimately branchto form the remainder of the capturing portion. In any case, byextending through the open proximal end 228, the main bundle 202 is ableto articulate relative to the capturing portion 226 withoutsignificantly reducing a profile of the open distal end 228.

FIG. 1D illustrates a condition where the main bundle 202 and capturingportion 226 articulate relative to one-another. Because the main bundle202 joins the capturing portion at a distance from the open proximal endmovement of the main bundle 202 relative to an axis 236 of the capturingportion 226 does not reduce a profile of the open proximal end 228. Ifthe main bundle 202 were affixed or connected to the open proximal end228, then any movement of the bundle 202 away from the capturingportion's axis 236 would exert a force on the open end. This force, inturn, would cause the open end to narrow or deform. By doing so, theopen end would not be able to uniformly expand against the lumen wall tocapture the obstruction.

Turning now to the construction of the device 200, as shown in FIGS. 1Band 1C, the main bundle or a leading wire 202 extends beyond the openproximal end 228 and forms the capturing portion. In one variation, theconstruction of the device relies on converging/diverging wires to formcontinuous shapes so that the device is completely joint or connectionfree. However, as noted herein, the leading wire or main bundle 202 canbe affixed to a structure that forms the capturing portion via anattachment point, joint, or junction. In addition, the structuresforming the capturing portion can be fabricated from such processes aslaser cutting of tubes, etching, metal injection molding, or any othersuch process.

The devices of the present invention can also include additionalfeatures to aid in removal of obstructions. For example, as shown inFIGS. 1B to 1C, the open proximal end 228 can include one or more petalsor flanges 238 extending radially outward. The flanges 238 allow device200 to have a flared structure at the open proximal end 228. In oneexample, the capturing portion 226 can be slightly oversized relative tothe body passage containing the obstruction or slightly larger than thecapturing portion. The flanges 238 provide an additional force againstthe wall of the passage to ensure that the device 200 is able tosurround or encapsulate the obstruction. In yet another feature, invariations of a system having a proximal and distal capturing portion,the flanges can serve to lock the proximal and distal capturing portionstogether once they encapsulate or surround an obstruction. This featureminimizes the chance that the obstruction escapes from the capturingportions as the device and obstruction are removed from the body lumen.

In additional variations, the main bundle can diverge to form thecapturing portion in multiple locations so long as the capturingportion's ability to articulate is not sacrificed. For example, the mainbundle can diverge in several locations along the capturing surface (notshown).

FIGS. 1B to 1C also shows an integrally formed reinforcement ring 240located along the length of the capturing surface 232 (i.e., on thetraversing wires). The reinforcement ring 240 can be a separate ordiscrete ring located on or in the capturing surface 232. Alternatively,or in combination, the reinforcement ring 240 can be a ring shape thatis integrally formed through arrangement of the wires 204 (as show inFIGS. 1B to 1C). The reinforcement ring 240 assists in expanding thedevice when deployed in the body lumen and/or prevents the device (e.g.,the open proximal end) from collapsing as the device moves within thelumen to secure the obstruction. The reinforcement ring 240 can comprisea single wire, or a twisted pair of wires. Alternatively, the rings donot need to extend entirely circumferentially around the capturingsurface. Instead, a reinforcement portion may extend between adjacenttraversing wires but does not necessarily extend around thecircumference of the capturing section. As noted herein, reinforcementportions may extend between adjacent traversing wires in multiplelocations.

FIGS. 2A to 2L illustrate additional variations of capturing portions226. FIG. 2A illustrates a variation having an integrated reinforcementring 240. Typically, the reinforcement ring 240 provides radial strengthto the capturing portion 226 to prevent collapse or deformation thatwould otherwise interfere with enveloping the obstruction. Areinforcement ring 240 may allow for use of wires that would otherwiseprovide unacceptable radial strength. For example, the reinforcementring 240 may permit use of smaller diameter wires thereby allowing thedevice 200 to compress to a smaller diameter during delivery via acatheter.

In addition to the reinforcement ring 240, FIG. 2A includes an openproximal end 228 having a number of petals/flanges 228. In thisvariation, although the flanges 238 intersect one another, they areindependently moveable.

FIG. 2B shows another variation of a device 200 where the capturingportion includes flanges 238 that are interwoven or connected withadjacent flanges 238. (Variations include bonding or otherwise joiningthe adjacent flanges together.) This feature provides the flanges 238with a higher radial strength that reduces the likelihood that theflanges 238 bend or distort when moving in the body lumen or removingthe obstruction.

FIG. 2C to 2D illustrate additional variations of devices havingcapturing portions 226 that have a basket type configuration. As shown,the capturing portions 226 and surface 232 comprise a denser mesh oftraversing wires that ultimately lead to flanges 238 at the openproximal end 228. In such variations, a first portion of the capturingsurface that is adjacent to the open proximal end has a low coveragedensity relative to the remaining portion of the capturing surfacehaving a higher coverage density that eventually forms the permeabledistal end 230. This construction lowers the lowering frictionalresistance of the first portion of the capturing surface when movingover or against the obstruction but allows the remaining portion of thecapturing surface to encapsulate and secure the obstruction.

As shown in FIG. 2C, the wires diverge from the main bundle towards thedistal end of the capturing portion 226 to form the permeable distal end230. The permeable distal end may actually have the same configurationas the capturing portion. In other words, the permeable distal end cansimply be an extension of the capturing surface that extends over thedistal end of the capturing portion.

Naturally, the divergence of the wires can occur over a length of thecapturing portion 226 rather than immediately at the distal end. Forexample, as show in FIG. 2D, the wires diverge towards a mid-section ofthe capturing portion and ultimately form the permeable distal end 230.

FIG. 2E illustrates a variation of a device 200 having multiplereinforcement rings 240. As noted above, the reinforcement rings provideadditional radial strength to the capturing portion 226 as the device200 moves within the body lumen and prevents distortion of the capturingportion 226. The rings do not need to extend around an entirecircumference of a device, variations include any number of supportsthat extend between adjacent traversing wires.

FIG. 2F illustrates an additional variation of a device 200 where theproximal flanges 238 taper or flare away from the capturing surface 232by an angle A. The tapering of the flanges 238 improves the ability ofthe flanges 238 to contact a wall of the vessel or passage as the device200 moves through the lumen. The angle A can be any angle. In addition,the angle A can be the same for all flanges 238. Alternatively, eachflange 238 can have differing degrees of a taper with some flanges beingrelatively straight while others taper.

FIG. 2G shows a variation of a device 200 where traversing wires 204forming the capturing surface 232 form a reinforcement structure 240rather than a reinforcement ring as noted above. This configurationreduces the likelihood that the traversing wires 204 deformlongitudinally, and less likely for the entire capturing portion 226 tocollapse as it travels through tortuous anatomy.

FIG. 2H shows a variation of a device 200 where the traversing wires 204twist when forming the capturing surface 232. The device can beconstructed starting with a non-twisting design, as shown above, andthen twisted (i.e. where one end of the capturing portion 226 rotatesrelative to another end). The final twisted shape can be heat set tohold the shape. Alternatively, the capturing surface can simply beconstructed into a twisted shape. This design provides advantages as thetwisted nature of the capturing surface 232 should translate over theobstruction with less effort due to the torque-like motion of wires 204as the physician pulls the device 200 over the obstruction. The twistingmotion or torque helps reduce the static friction to a greater degreeand generally increases the momentum of the capturing portion 226.Simply pulling this variation of the device in a proximal directioncauses the twisted traversing wires 204 to translate longitudinally androtationally over the obstruction in the same manner as if torque werebeing applied to the device 200.

The twisting configuration shown in FIG. 2H is also less likely tocollapse as it goes around a bend in a vessel or other body lumen. Eachtraversing wire 204 travels in and out of a plane of the direction oftravel of the device. This minimizes the contact between the traversingwire 204 and the wall of the body passage as the device 200 travelsaround a curve in the body passage.

FIG. 2I shows a variation of a device 200 where the capturing surface232 of the capturing portion 226 has an “open side” (i.e., the capturingsurface 232 does not circumferentially surround the main bundle 202.Accordingly, the reinforcement ring 240 and flanges 230 do not fullysurround the main bundle 202 as well. As a result, in this variation thecapturing portion 226 only includes 3 sides and 3 corresponding flanges238. It is believed that this “open sided” design better conforms to theinner diameter of a vessel.

FIG. 2J illustrates another variation of a device 200 where thecapturing surface portion 232 of the device 200 has an open side. Theopen side construction reduces friction between the device and the bodylumen and between the device and the obstruction. In an additionalvariation, the openings in the proximal and distal end can be orientedin any configuration. For example, the openings can be 180 degreesrotated from one another. In addition, it is desirable to over-size theprofile of the device relative to the diameter of the body lumen. Anopen ended, semi-circular or partial circular sectional profile makes iteasier to oversize the device for the intended body passage and allowsthe device to better conform to the size of the vessel. In such cases,the capturing portion is open at one side of the device to allow thecapturing portion to better expand against the vessel. As shown, themain bundle 202 extends through the capturing portion 226 to thepermeable distal end 230. In this variation, the device 200 is not shownwith petals/flanges on the open proximal end 228. However, petals can beincorporated into the design on all sides except for the open side.

As shown, the device includes mechanical features that assist in removalof the obstruction. These features can be hooks, fibers, barb, or anysuch structure. For example, such mechanical features are illustrated onFIG. 2J. Any portion of the capturing portion or even the device canhave such hooks, fibers, or barbs 154 that grip into the obstruction asthe device surrounds the obstruction. It will be important that suchfeatures prevent the obstruction from sliding proximally but do nothinder the ability of the practitioner to remove the device from thebody.

FIG. 2K illustrates another variation of a device 200 having a wire 202extending to a distal end 230 of a capturing portion 226. In thisvariation the capturing portion 226 is fabricated from a stent-typestructure. As noted above, it is within the scope of this disclosure touse any type of similar structure such as a laser cut tube, a chemicallyetched or photo etched tube, a polymer or metal injection moldedstructure, a basket, a filter, a bag, a coil, a helical wire structuresa mesh, a single wound wire, a film, a membrane, a polymer covering, ora plurality of crossing wires as the capturing portion 226 so long asthe device can be compressed to a small size for delivery and expandafter traversing the obstruction. The illustrated variation also shows acovering 270 located on the distal end 230 of the capturing portion 226.The length of the polymeric covering 270 can vary across the capturingportion 226 to prevent the obstruction from escaping as the device istranslated over the obstruction. Furthermore, the covering 270 can bepolymeric or a wire mesh. However, typically the covering has sufficientporosity to allow blood to flow through the device 200.

FIG. 2L illustrates another feature for use with system describedherein. In this variation, the system includes a proximal capturingportion 260 located on an exterior of a delivery sheath 106. The mainbundle 202 extends through the sheath 106 to a distal capturing portion(not shown). As discussed below, the proximal capturing portion 260 canbe similar to the distal capturing portions 226 described herein withthe exception that the distal end 262 of the proximal capturing portionis open while the proximal end 264 of the proximal capturing portion isclosed. Furthermore, the proximal capturing portion 260 articulates withrespect to the sheath 106 much in the same manner as the distalcapturing portion 226 articulates relative to the main bundle 202. Inthis variation, the proximal end 264 of the proximal capturing portion260 is tapered or has a smaller profile than the remaining proximalcapturing portion 260. Such a feature may be useful to improve thedeliverability of the device to the intended site as well as to maneuveraround any obstructions within the body passage. In addition, as notedbelow (see e.g., FIG. 4F), the proximal capturing portion 260 can becompressed about the obstruction to improve the ability of the system toremove the obstruction.

FIG. 3A illustrates the main bundle 202 as having a curved or bendportion 252. This pre-set shape assists in orienting the capturingportion 226 within the body passage since the bend will cause the deviceto bias against a wall of the body passage.

FIGS. 3B and 3C show cross sectional views taken along the line A-A inFIG. 3A. As shown, the wire form construction described herein allowsfor a number of configurations depending on the particular application.For example, the individual wires 204 (as shown in FIG. 1B) maythemselves comprise a bundle of smaller wires or filaments. In addition,the wires can be selected from materials such as stainless steel,titanium, platinum, gold, iridium, tantalum, nitinol, alloys, and/orpolymeric strands. In addition, the wires used in a device may comprisea heterogeneous structure by using combinations of wires of differentmaterials to produce a device having the particular desired properties.For example, one or more wires in the device may comprise a shape memoryor superelastic alloy to impart predetermined shapes or resiliency tothe device. In some variations, the mechanical properties of selectwires can be altered. In such a case, the select wires can be treated toalter properties including: brittleness, ductility, elasticity,hardness, malleability, plasticity, strength, and toughness.

The device may include a number of radiopaque wires, such as gold andplatinum for improved visibility under fluoroscopic imaging. In otherwords, any combination of materials may be incorporated into the device.In addition to the materials, the size of the wires may vary as needed.For example, the diameters of the wires may be the same or may vary asneeded.

In addition, the individual wires may have cross-sectional shapesranging from circular, oval, d-shaped, rectangular shape, etc. FIG. 3Billustrates one possible variation in which a number of circular wires204 are included with a d-shaped wire 205. Moreover, the device is notlimited to having wires having the same cross-sectional shape or size.Instead, the device can have wires having different cross-sectionalshapes. For example, as shown in FIG. 3C, one or more wires 205 can havea different cross-sectional shape or size than a reminder of the wires204. Clearly, any number of variations is within the scope of thisdisclosure.

To illustrate one such example, a device can have 8-12 wires made of0.003″ round superelastic material (e.g., nitinol). The device mayadditionally have 2-4 wires made from 0.002″ platinum for fluoroscopy.Of the 8-12 nitinol wires, 1-4 of these wires can be made of a largerdiameter or different cross-section to increase the overall strength ofthe device. Finally, a couple of polymer fibers can be added where thefibers have a desired surface property for clot adherence, etc. Such acombination of wires provides a composite device with properties notconventionally possible in view of other formation means (such as lasercutting or etching the shape from a tube or joining materials withwelds, etc.). Clearly, any number of permutations is possible given theprinciples of the invention.

In another example, the device may be fabricated from wires formed froma polymeric material or composite blend of polymeric materials. Thepolymeric composite can be selected such that it is very floppy until itis exposed to either the body fluids and or some other deliveredactivator that causes the polymer to further polymerize or stiffen forstrength. Various coatings could protect the polymer from furtherpolymerizing before the device is properly placed. The coatings couldprovide a specific duration for placement (e.g., 5 minutes) after whichthe covering degrades or is activated with an agent (that doesn't affectthe surrounding tissues) allowing the device to increase in stiffness sothat it doesn't stretch as the thrombus is pulled out. For example,shape memory polymers would allow the device to increase in stiffness.

In another variation, one or more of the wires used in the device maycomprise a Drawn Filled Tube (DFT) such as those provided by Fort WayneMetals, Fort Wayne, Ind. As shown in FIG. 3D, such a DFT wire 252comprise a first material or shell 208 over a second material 210 havingproperties different from the outer shell. While a variety of materialscan be used, one variation under the present devices includes a DFT wirehaving a superelastic (e.g., Nitinol) outer tube with a radiopaquematerial within the super-elastic outer shell. For example, theradiopaque material can include any commercially used radiopaquematerial, including but not limited to platinum, iridium, gold,tantalum, or similar alloy. One benefit of making a capturing portionfrom the DFT wire noted above, is that rather than having one or moremarkers over the capturing portion, the entire capturing portion can befabricated from a super-elastic material while, at the same time, thesuper-elastic capturing portion is made radiopaque given the core ofradiopaque material within the super-elastic shell. Clearly, anycomposite DFT wire 252 can be incorporated into the system and capturingportions described herein.

FIG. 4A shows a working end of a system 10 for removing an obstructionfrom a body lumen. In this variation, the system 10 includes a mainbundle 202 and capturing portion 226 extending out of a micro-catheteror catheter 102. The micro-catheter 102 can optionally include aproximal foot 256 that can slide axially over main bundle 202 and can bevariably positioned in relation to the capturing portion 226. Theproximal foot 256 can include any number of configurations apart fromthe petal/flange 258 configuration (i.e., the foot can be a balloon,coil, shoulder, etc. where such structures simply replace the petals inFIG. 4A). In any case, the proximal foot 256 provides an increasedsurface area that provides an opposing force to the capturing portion226, where the opposing force aids the movement of the obstructionwithin the capturing portion 226. Alternatively, the proximal footstabilizes the obstruction and keeps the obstruction from moving withthe capturing portion until the capturing portion envelops theobstruction.

The size of the proximal foot 256 can be adjusted depending on thetarget site anatomy. For example, a larger surface area can be employedif the target site is within a bifurcation of the body passage. The sizeof the proximal foot 256 can also be adjustable during the procedure.For example, in the case of a petal/flange 258 configuration, the petals258 can assume a larger size to initially stabilize the obstruction andthen reduce in size to allow the obstruction to be completely engulfedby capturing section 226.

The proximal foot 256 can extend from an interior of the catheter 102,such as from within the internal lumen of the catheter, or from anadditional lumen within a wall of the catheter. Alternatively, theproximal foot 256 can be permanently affixed to the catheter 102. Insuch a case, a separate catheter (without a proximal foot) can beemployed to traverse the obstruction for deployment of the devicedistally to the obstruction. Once the device is deployed, the catheterscan be exchanged to provide the proximal foot. In an additionalvariation, the proximal foot 256 can be affixed to a delivery sheath (asdescribed below) and be collapsed within the catheter, where advancementout of the catheter expands the proximal foot 256 so that it mayfunction as described above.

FIG. 4B illustrates another variation of the system 10 where the systemincludes a proximal capturing portion 260 located on an exterior of adelivery sheath 106. Naturally, the proximal capturing portion 260 couldalso be affixed to an exterior of a micro-catheter. The proximalcapturing portion 260 is similar to the capturing portions 226 describedherein with the exception that the distal end 262 of the proximalcapturing portion is open while the proximal end 264 of the proximalcapturing portion is closed. In this variation, the capturing portion226 and main bundle 202 move relative to the proximal capturing portion260 to capture an obstruction. Furthermore, the proximal capturingportion 260 articulates with respect to the sheath 106 much in the samemanner as the distal capturing portion 226 articulates relative to themain bundle 202. As shown, the petals 238 on the open ends 228 and 262can interact to nest once the capturing portions 226 and 260 are movedsufficiently close to one another. The outward force caused by theretained obstruction provides a frictional interaction between adjacentpetals/flanges 238 to maintain the nesting. Variations of the deviceinclude additional structures, such as springs, hooks, barbs, etc, tocause the open ends 228 and 262 to interlock. As noted above, a separatecatheter can be used to initially deploy the capturing portion 226beyond the obstruction. Although the capturing portions shown have thesame configuration, the capturing portions 226 and 260 used in any givensystem do not have to match in size, shape, and configuration. Forexample, the proximal capturing portion can be impermeable to flow whilethe distal capturing portion allows flow. In another example, one basketmay be undersized relative to the other to improve nesting.

In any case, the construction of the system 10 shown in FIG. 4B includesopen ends 228 and 262 of capturing portions 226 and 260 that areunconnected. Accordingly, as the capturing portions 226 and 260 movetowards one another as a result of the main bundle 202 translatingrelative to the delivery sheath 106 the open ends are free to articulatearound the main bundle 202 and delivery sheath 106 respectively toremain expanded against the lumen wall.

FIGS. 4C to 4E illustrate a variation of a system for delivery of thecapturing portions 220 and 260. FIG. 4C shows the proximal 260 capturingportion affixed to a delivery sheath 106. In alternate variations, theproximal capturing portion 260 can be replaced with a proximal foot (notshown). As noted above, the main bundle or leading wire 202 extendsthrough the delivery sheath 106 and connects to the distal capturingportion 200 beyond the opening 228 of the distal capturing portion 200.The main bundle or leading wire 202 extends through the proximalcapturing portion 260. This allows the free ends of the capturingportions 228 and 262 to remain relatively unattached so that they canarticulate and conform to the curvature of the vessels (see below,especially FIGS. 5A to 6E). The capturing portions 200 and 260, mainbundle 202 and delivery sheath 106 extend through a microcatheter 102.

FIG. 4D illustrates a state of deployment after the microcatheter 102traverses the obstruction (not shown). Once the microcatheter 102 isdistal to the obstruction, the distal capturing portion 200 deploys fromthe end of the microcatheter 202. As noted herein, the capturingportions can self-expand or can expand upon actuation by the physician.In any case, the distal capturing portion 200 should be sufficientlycollapsible to remain within the microcatheter 102 for deployment distalto an obstruction. To deploy the distal capturing portion 200 from thecatheter 102, the main bundle 202 can translate to push the distalcapturing portion 200 to eject it from the catheter 102. Alternatively,the microcatheter 102 can be withdrawn from the distal capturing portion200.

FIG. 4E illustrates the deployment state after the catheter 102 iswithdrawn proximal to the obstruction and after the proximal captureportion 260 is delivered from the microcatheter 102. As noted above, theproximal capture portion 260 can be affixed to an exterior of thecatheter, in which case the catheter may be either de-sheathed orexchanged. Alternatively, and as shown, the proximal capturing portion260 is affixed to a delivery sheath 106 and is fabricated to collapsewithin the microcatheter for ultimate deployment, whereby translatingthe sheath 106 delivers the proximal portion 260 from the microcatheter.

FIG. 4F shows another aspect of the system 10 where the proximal end 264of the proximal capturing portion 260 is collapsed or compressed aboutan obstruction 2 prior to translation of the obstruction 2 within thevessel. In this illustration, the proximal capturing portion 260 iscompressible by advancing the catheter 102 over the closed proximal end264 of the capturing portion 260. In such a case, the proximal capturingportion 260 is slidable within and relative to the catheter 102.Naturally, variations may include compressing the proximal end 264during translation of the obstruction 2. In either case, the proximalcapturing portion 260 can be compressed in a number of different ways.For instance, the proximal basket can be compressed using a catheter 102(as shown), or the delivery sheath 106, or any other number ofmechanisms (not illustrated).

As shown, the proximal end 264 can be compressed using a sheath 106.However, other means of compressing may be employed (e.g., a loopstructure, a tube over the sheath, a draw-string configuration, etc.) Inuse, once the distal capturing portion 200 is deployed distally to theobstruction 2 and the catheter 102 is withdrawn proximal to theobstruction 2, the proximal capturing portion 260 is deployed. As theproximal capturing portion 260 partially (or totally) engulfs theobstruction 2, the physician can collapse or compress the proximalcapturing portion 260 to better secure the obstruction within the system10.

It is noted that any number of shapes, configurations, as well as anynumber of joined wires may be contemplated to form devices under thepresent disclosure. However, variations of the invention includeselecting a number of wires to produce specific structural properties tothe device. For example, the devices can have any number of wires wherethe limit is determined by the ability to produce a device of asufficiently small size to access the area containing the obstruction.However, in some cases, it may be desired that wires are chosen toimpart specified characteristics. For example, in the illustratedvariation, the main bundle may comprise any number of wires that do notdiverge to form subsequent shapes in the device. In other words, not allof the wires forming a section are required to diverge to form anadjacent section. Instead, these non-diverging wires may simply “loop”back away from the device. In an additional variation, one or more wiresmay diverge to form a particular portion of the capturing portion (e.g.,the closed end, traversing wires, etc.). Then the wires can loop back toconverge again with the main bundle.

FIGS. 5A to 5B illustrate one benefit of affixing a leading wire orbundle of wires 202 beyond a proximal opening 228 of a capturing portion226. FIG. 5A illustrates a basket type structure 90 where a wire 202 isaffixed to a proximal end 92. As shown, as the leading wire 202 pullsthe basket 90 through tortuous anatomy 6, the force component pullingaway from an axis of the device 90 causes the proximal open end 92 toconstrict or reduce in size. As shown, as the proximal end 92 approachesthe obstruction 2 the perimeter of the end is not placed against thewalls of the body passage 6. As a result, the constricted opening 92places an increased axial force on the obstruction 2 as the basket 90translates over the obstruction 2 (because the proximal end 92 pushesagainst the obstruction rather than sliding around it), makingencapsulation of the obstruction more difficult and possible leading tovascular damage.

FIG. 5B shows a device 200 according to the principles disclosed herein.The leading wire 202 is affixed to the distal end 230 of the capturingportion 226. As the main bundle 202 is pulled through the curvedvascular path, the capturing portion 226 pivots or articulates about thebundle 202 and remains aligned with the axis of the vessel. As a resultany misalignment between the leading wire 202 and an axis of thecapturing portion 226 does not affect the open proximal end 228. Asnoted above, some closing of the open proximal end may occur, though itwill not be sufficient to interfere with the obstruction as thecapturing portion moves over the obstruction. Such a configurationallows the perimeter of the open proximal end 228 to remain against thewall of the passage 6. As shown, because the open proximal end 228 isnot constricted, the open proximal end 228 is better suited to slidearound the obstruction for eventual removal.

FIGS. 6A to 6E show one example of the deployment of a variation of adevice according to the present invention about an obstruction in avessel. The figures are intended to demonstrate the initial placement ofthe device immediately prior to removal of the obstruction.

FIG. 6A illustrates an obstruction 2 lodged within a body lumen orvessel 6. In the case where the vessel is a cerebral artery, theobstruction may result in an ischemic stroke. Using standardinterventional catheterization techniques, a microcatheter 102 andguidewire 104 traverse the obstruction. The microcatheter 102 may beadvanced through the obstruction 2. Alternatively, the microcatheter 102may “push” aside the obstruction and is advanced around the obstruction.In any case, the microcatheter 102 travels from the near end 3 (orproximal side) of the obstruction 2 to the far end 4 (or distal side) ofthe obstruction 2. It is noted that the catheter 102 may be centered oroff-center with respect to the obstruction 2. Furthermore, the devicemay or may not be used with a guidewire to navigate to the site andtraverse the obstruction.

Some variations of the device may be placed without an accompanyingguidewire. Moreover, the structures discussed herein may be directlyincorporated into a guidewire assembly where deployment may require asheath or other covering to release the components from constraint.

FIG. 6B illustrates deployment of a capturing portion 226 and mainbundle 202 of the device 200 from within the microcatheter 102 distal tothe obstruction 2. Accordingly, in most variations, the capturingportion 226 is designed to compress within the catheter 102 and expandupon deployment. Alternatively, the device may be actuated to assume thedesired shape (e.g., upon reaching a transition temperature where one ormore wires comprise a shape memory alloy).

FIG. 6C shows withdrawal of the microcatheter 102 to the proximal side 3of the obstruction 2 and deployment of a proximal capturing portion 260(in alternate variations, a proximal foot can be used or the capturingportion 226 alone can be used). Again, the catheter 102 can be exchangedfor a catheter 102 having a proximal capturing portion 260.Alternatively, and as shown in the accompanying figures, the proximalcapturing portion 260 can be affixed to a delivery sheath 106 that isfed through the microcatheter 102.

As also shown in the figure, the main bundle 202 and capturing portionsbecome misaligned due to the tortuousity of the anatomy. However,because the capturing portions 226 and 260 are able to pivot orarticulate relative to the main bundle 202 and catheter 102 or sheath106, the open ends are able to remain against the lumen wall. Inconventional devices where the open end is attached to either a wire orcatheter, when the wire or catheter bends in the anatomy, the forcesexerted on the open ends deform or distort the end to assume a reducedprofile. Accordingly, the physician may have difficulty in removing anobstruction if the profile of the open end becomes reduced in size.Closing of the open end can also result in vascular damage if thephysician applies too much force in translating the device.

FIG. 6D shows movement of the capturing portions 226 and 260 adjacent tothe obstruction 2. The proximal capturing portion 260 can remainstationary or may be advanced relative to the distal capturing portion226. Regardless, the physician is able to ensnare the obstruction 2within the cavities defined by the capturing portions 226 and 260. FIG.6E illustrates the system as the two capturing portions are drawntogether. For purposes of clarity, the obstruction is not shown. Uponsufficient advancement of the capturing portion 226 and proximalcapturing portion 260 relative to one-another, flanges 238 on therespective open ends can interlock. This feature provides added safetyin removing the device as the obstruction is encapsulated between thetwo nested portions.

FIG. 6F illustrates a device 200 after securing an obstruction between aproximal 260 and distal 226 capturing sections. As shown, the capturedobstruction 2 is held between capturing portions 226 and 260 where theflanges 238 nest within one-another to “lock” the capturing portionstogether. In some variations of the device, one of the capturingportions can be undersized relative to the other. This configurationallows for the undersized capturing portion to become further compressedas the devices are pulled together. The compression of the capturingsurface then serves to further compress the obstruction 2 capturedwithin the device.

FIGS. 7A to 7B illustrate coverings 270. Although the coverings arelocated on both capturing portions 200 and 260, only one or morecapturing portions can include coverings 270. The covering 270 caninclude a strand wrapped or woven about the section, a polymer film, ora dipped polymer coating such as silicone, urethane, etc. The coating oneither capturing portion can be solid or porous. In the latter case,blood can continue to flow through the coating. In one variation, theproximal capturing portion 260 could employ a solid covering 270 whilethe distal capturing portion 200 could include a porous covering 270. Insuch a case, blood or other fluid flow could be temporarily halted bythe presence of the solid covering 270 to assist in removal of theobstruction

FIGS. 8A to 8B illustrate a system with a distal 200 and proximal 206capturing portions with an additional set of fibers 272 extending alongthe inside of portion 200 and along a main bundle or leading wire 202.As the device ensnares an obstruction 2 the fibers are tensioned so thatthey surround the clot 2 within the capturing portions 200 and 260, asshown in FIG. 8B. In addition, the proximal capturing portion 260 and/ordelivery sheath 106 can be rotated relative to the distal capturingportion 200 to twist the fibers 272 allowing improved capture of theobstruction 2.

FIG. 9 illustrates another variation of the system where the main bundle202 includes a medial foot 274. The construction of the medial foot 274can be similar to that of the proximal foot discussed above (e.g., wireslooped into a petal configuration.) However, the medial foot includes asurface area or diameter larger than a diameter of the main bundle. Inany case, the increased surface area of the medial foot 274 provides anincreased resistance to the obstruction 2 as the distal capturingportion 200 and main bundle 202 are pulled in a proximal directiontowards an obstruction 2. The medial foot 274 engages the obstruction 2to partially displace or loosen the obstruction from the walls of thebody passage. The medial foot 274 can be slidably located on the mainbundle such that after a threshold force, the medial foot moves withinthe distal capturing portion 200. The main bundle 202 can include anynumber of medial feet 274.

Although the illustrated variation shown above comprise open-ended,circular, looped or partial loop shape cross sectional areas, variationsof the capturing portions can include any number of shapes. For example,such a shape can include a circle, an arcuate shape, a partial circularshape, a loop, an oval, a square, a rectangle, a polygon, an overlappingloop, a pair of semi-circles, etc.) The various shapes may be heat setto be either self-expanding (i.e., superelastic) or the use of shapememory alloys can allow for the device to assume the particular shapeupon reaching a desired transition temperature.

The exemplary shapes discussed above permit the shaped section to adjustin diameter in response to placement in varying diameters of bodylumens. It is noted that a device may have different shaped sections ondifferent ends of the device.

While many different shapes are contemplated to be within the scope ofthis disclosure, the shapes will depend upon the ultimate application ofthe device. As noted herein, the illustrated examples have particularapplicability in retrieving obstructions from the vasculature.Accordingly, for these applications the shaped sections should form ashape so that they can expand against a vessel wall without causingtrauma to the vessel. For example, upon release from the catheter, theshaped section can assume their resting shape and expand within thevessel. The resting shape can be constructed to have a size slightlygreater than that of the vessel. Sizing the device relative to thetarget vessel may assist in placing the parts of the device against avessel.

In an additional aspect, the shaped sections may be designed to have anunconstrained shape that is larger than the intended target vessel orsimply different than a cross sectional profile of the intended vessel(i.e., not circular or tubular, but e.g., linear or other differentshape). In such an example, as the shaped section is released from thedelivery catheter, the shape section attempts to return to theunconstrained shape. In those variations where the unconstrained shapeis different from the circular profile of the vessel, the leading wireassumes a shape that accommodates the vessel but is more rigid andstable since its unconstrained shape is entirely different from that ofthe vessel. In other words, the shaped section continually exerts anoutward force on the vessel.

In yet another aspect, the shaped sections shown herein may notnecessarily lie in the same plane. Instead, they can be axially spacedby an offset. One benefit of constructing the device to have non-planarshaped section is that the configuration might allow for delivery of thedevice through a smaller microcatheter because the shaped sections donot interfere with one another when collapsed to fit within themicrocatheter.

Another aspect applicable to all variations of the devices is toconfigure the devices (whether the traversing filament or thesurrounding portion) for better adherence to the obstruction. One suchmode includes the use of coatings that bond to certain clots (or othermaterials causing the obstruction.) For example, the wires may be coatedwith a hydrogel or adhesive that bonds to a thrombus. Accordingly, asthe device secures about a clot, the combination of the additive and themechanical structure of the device may improve the effectiveness of thedevice in removing the obstruction. Coatings may also be combined withthe capturing portions or catheter to improve the ability of the deviceto encapsulate and remove the obstruction (e.g., a hydrophilic coating).

Such improvements may also be mechanical or structural. Any portion ofthe capturing portion can have hooks, fibers, or barbs 154 (see e.g.,FIG. 2J) that grip into the obstruction as the device surrounds theobstruction. The hooks, fibers, or barbs 154 can be incorporated intoany portion of the device. However, it will be important that suchfeatures do not hinder the ability of the practitioner to remove thedevice from the body.

In addition to additives, the device can be coupled to an RF or otherpower source (such as 14 or 16 in FIG. 1A), to allow current, ultrasoundor RF energy to transmit through the device and induce clotting or causeadditional coagulation of a clot or other the obstruction.

The methods described herein may also include treating the obstructionprior to attempting to remove the obstruction. Such a treatment caninclude applying a chemical or pharmaceutical agent with the goal ofmaking the occlusion shrink or to make it more rigid for easier removal.Such agents include, but are not limited to chemotherapy drugs, orsolutions, a mild formalin, or aldehyde solution.

As for other details of the present invention, materials andmanufacturing techniques may be employed as within the level of thosewith skill in the relevant art. The same may hold true with respect tomethod-based aspects of the invention in terms of additional acts thatare commonly or logically employed. In addition, though the inventionhas been described in reference to several examples, optionallyincorporating various features, the invention is not to be limited tothat which is described or indicated as contemplated with respect toeach variation of the invention.

It is important to note that where possible, aspects of the variousdescribed embodiments, or the embodiments themselves can be combined.Where such combinations are intended to be within the scope of thisdisclosure.

Various changes may be made to the invention described and equivalents(whether recited herein or not included for the sake of some brevity)may be substituted without departing from the true spirit and scope ofthe invention. Also, any optional feature of the inventive variationsmay be set forth and claimed independently, or in combination with anyone or more of the features described herein. Accordingly, the inventioncontemplates combinations of various aspects of the embodiments orcombinations of the embodiments themselves, where possible. Reference toa singular item, includes the possibility that there are plural of thesame items present. More specifically, as used herein and in theappended claims, the singular forms “a,” “and,” “said,” and “the”include plural references unless the context clearly dictates otherwise.

We claim:
 1. A medical device for removing an obstruction from a bloodvessel, the medical device comprising: a stent-type structurecomprising: a connecting portion having a proximal end and a distal end,wherein the proximal end of the connecting portion is configured to becoupled to an elongate delivery member; a first capturing portiondiverging from the connecting portion, the first capturing portionhaving a distal end, a proximal end, and a first capturing surfaceextending between the distal and proximal ends of the first capturingportion and defining an axially extending first cavity, wherein adiameter of the first capturing portion is greater at the distal end ofthe first capturing portion than at the proximal end of the firstcapturing portion, and wherein the distal end of the first capturingportion includes a plurality of first flanges, the plurality of firstflanges being spaced apart about a circumference of the distal end ofthe first capturing portion, wherein each first flange includes at leastone wire extending continuously along a periphery of the respectivefirst flange; a second capturing portion diverging from the connectingportion, the second capturing portion having a distal end, a proximalend, and a second capturing surface extending between the distal andproximal ends of the second capturing portion and defining an axiallyextending second cavity, wherein a diameter of the second capturingportion is greater at the proximal end of the second capturing portionthan at the distal end of the second capturing portion, wherein theproximal end of the second capturing portion includes a plurality ofsecond flanges, and wherein each second flange includes at least onewire extending continuously along a periphery of the respective secondflange; wherein the connecting portion extends through the firstcapturing portion and the second capturing portion.
 2. The medicaldevice of claim 1, wherein a side of the first capturing surface isopen.
 3. The medical device of claim 1, wherein a side of the secondcapturing surface is open.
 4. The medical device of claim 1, wherein thefirst flanges extend radially away from the first cavity.
 5. The medicaldevice of claim 1, wherein the second flanges extend radially away fromthe second cavity.
 6. The medical device of claim 1, wherein thestent-type structure is self-expandable.
 7. The medical device of claim1, wherein the first capturing surface circumferentially surrounds theconnecting portion.
 8. The medical device of claim 1, wherein the secondcapturing surface circumferentially surrounds the connecting portion. 9.The medical device of claim 1, wherein the stent-type structure is madeof a metal alloy.
 10. The medical device of claim 9, where the metalalloy comprises an alloy selected from the group consisting of stainlesssteel, titanium, platinum, gold, iridium, tantalum, nitinol, andcombinations thereof.
 11. The medical device of claim 1, furthercomprising at least one radiopaque material located on the firstcapturing portion.
 12. The medical device of claim 1, further comprisingat least one radiopaque material located on the second capturingportion.
 13. The medical device of claim 1, wherein the first capturingportion is jointless.
 14. The medical device of claim 1, wherein thesecond capturing portion is jointless.
 15. A medical device for removingan obstruction from a blood vessel, the medical device comprising: astent-type structure comprising: a connecting portion having a proximalend and a distal end, wherein the proximal end of the connecting portionis configured to be coupled to an elongate delivery member; a firstcapturing portion diverging from the connecting portion, the firstcapturing portion having a distal end, a proximal end, and a firstcapturing surface extending between the distal and proximal ends of thefirst capturing portion and defining an axially extending first cavity,wherein a diameter of the first capturing portion is greater at thedistal end of the first capturing portion than at the proximal end ofthe first capturing portion, wherein the distal end of the firstcapturing portion includes a plurality of first flanges defining anundulating surface, and wherein each first flange includes at least onewire extending continuously along an edge of the respective firstflange; and a second capturing portion diverging from the connectingportion, the second capturing portion having a distal end, a proximalend, and a second capturing surface extending between the distal andproximal ends of the second capturing portion and defining an axiallyextending second cavity, wherein a diameter of the second capturingportion is greater at the proximal end of the second capturing portionthan at the distal end of the second capturing portion, wherein theproximal end of the second capturing portion includes a plurality ofsecond flanges, and wherein each second flange includes at least onewire extending continuously along a periphery of the respective secondflange; wherein the connecting portion extends through the firstcapturing portion and the second capturing portion.